If anyone is interested in a cheap pre-loved (but perfectly working and tested) GPS module, plays nicely with Arduino, please feel free to come and get them. We used them for a project which is now defunct, and have no use for them.

They actually end up about £20 for one, including delivery and VAT. However, I was attracted by the simplicity so I took the plunge. Wired it up last night and I even got a fix (eventually) in the middle of my living room floor.

The great thing about the examples here is they interface directly to Arduino. However for less than half the price of these, you can get a brand new(obsolete) Garmin GPS 15-F module which has external antenna connector for £8. Just requires some 5V->3.3V conversion!! I am not affiliated to the seller, just wanted to share with you all another option for 'cheap' Arduino GPS.

By the way, has anybody tried to make an OS Maps Sat-Nav on Arduino? I have a Sainsmart Mega 2560/SD TFT setup, and I have tentatively produced a successful navigation system.....at least as far as a proof of concept.

I am potentially looking for any help that could be offered to speed up the map drawing.......(18 seconds for a 240x240 pixel map or 1/2 Km with 20 pixel overlap) and also parsing of palettised BMP. My current program requires 24bit colour depth BMP images which are HUGE compared to 8bit colour with palette.

The system would not be any good for a car, as the rate of travel would exceed the refresh rate of the maps, but for walking or cycling, I am optimistic it would have some potential.